Margins on new train items in O gauge are very tight. You can’t equate those margins with mass market items, or even the days when Lionel trains were sold as seasonal toys in the postwar era.
That said, we might see shipping deals and special deals on older (but still new) items that sellers want to move this season.
However, Black Friday sales (literally the sales from the day after Thanksgiving Day) are traditionally an in-store sales rush. So don’t expect O gauge dealers to offer special one-day deals online. Your local hobby shop might offer some one-day deals.